Heat spreader with a liquid-vapor separation structure

ABSTRACT

A heat spreader with a liquid-vapor separation structure includes a first panel, a second panel bonded with the first panel and defining therebetween an enclosed accommodation chamber, multiple spacer members arranged spaced apart from one another in the accommodation chamber and abutted between the first panel and the second panel and defining multiple vapor passages and liquid passages therebetween and dividing the accommodation chamber into a heat-absorbing zone and a condensing zone that are disposed in communication with each other through the vapor passages and the liquid passages, a first wick material partially disposed in the liquid passages and partially disposed in the heat-absorbing zone and the condensing zone, and a working fluid filled in the accommodation chamber.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to cooling technology and moreparticularly, to a heat spreader with a liquid-vapor separationstructure.

2. Description of the Related Art

With the continuous growing trend of global electronics industry market,many electronic products (such as LED light module, computers and mobilephones, etc . . . ) have become an indispensable part of people's lives.However, with continuous development of these electronic products, inorder to achieve enhanced product performance, the product compositionunits are easy to produce large amounts of heat during operation. Whenthese product composition units have a certain degree of waste heataccumulated therein, the working efficiency of these electronic productswill be lowered, or the lifespan of these electronic products will beshortened. Therefore, most electronic products have heat pipes or heatspreaders (vapor chambers) mounted in their heat-generating units andincorporated with radiation fins or cooling fans to form a coolingsystem for quick dissipation of waste heat. A heat pipe isone-dimensional and linear structure that transfers heat from one singlepoint to another while a heat spreader (vapor chamber) is a plate thatspreads heat from one point to a two-dimensional area. A heat spreadercan rapidly and evenly spread out heat energy, accelerating thermalcycle efficiency. Therefore, heat spreaders (vapor chambers) have betterthermal performance than heat pipes. Taiwan Patent Publication No.1476361 discloses a heat spreader and the formation of the wickstructure of the heat spreader. According to this design, the heatspreader comprises a bottom panel, a cover panel, a plurality of supportprojections, a wick structure and a working fluid. The cover panel isclosed on the bottom panel and sealed such that an accommodation chamberis defined in between the cover panel and the bottom panel. The supportprojections are directly formed on the inner wall of the bottom panel orcover panel. The wick structure is coated on the surface of each supportprojection, the inside wall of the bottom panel and the inside wall ofthe cover panel. The working fluid is filled in the accommodationchamber to enhance the thermal conducting efficiency and speed of theheat spreader.

Although the heat spreader uses the support projections to enhance itssupporting strength, the arrangement of the support projections makesthe wick structure to exhibit an undulating configuration. Duringthermal cycling, the working fluid must go through apertures in the wickstructure in between the support projections. This undulating structurewill affect the reflux rate of the working fluid. Further, the workingfluid flows in the accommodation chamber in a liquid-vapor coexistencemanner. The flowing of the liquid phase and vapor phase of the workingfluid in different directions may also cause a reduction in the massflux during thermal cycling, further affecting the cooling effect.

Further, because the support projections of the aforesaid prior art heattransfer respectively consist of two solid semi-spheres of unequalradius and arranged spaced away from one another, if the heat spreaderis mounted in a space that needs to bear a load or tends to becompressed, the stress point will be focused on the top side of thesemi-spheres, thus, if the heat spreader is compressed, the pressurecannot be evenly distributed in all directions, leading to structuraldamage. Therefore, an improvement on the structural support of a heatspreader is desired.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances inview. It is the main object of the present invention to provide a heatspreader with a liquid-vapor separation structure, which has multiplevapor passages and at least one liquid passage arranged therein toconstrain the vapor phase and liquid phase of a working fluid to flow indifferent passages, increasing the mass flux of the working fluid in thevapor-liquid circulation system to achieve better heat dissipationperformance.

It is another object of the present invention to provide a heat spreaderwith a liquid-vapor separation structure, which has multiple spacermembers arranged therein and abutted between at least one first paneland a second panel thereof to form a strong support structure, achievinga better supporting effect.

To achieve these and other objects of the present invention, a heatspreader with a liquid-vapor separation structure comprises at least onefirst panel, a second panel, a plurality of spacer members, at least onepiece of first wick, and a working fluid. The second panel bonded withthe at least one first panel, defining with the at least one first panelat least one enclosed accommodation chamber therebetween. The spacermembers are abutted between the at least one first panel and the secondpanel and arranged spaced apart from one another in the at least oneenclosed accommodation chamber, defining a plurality of vapor passagesand at least one liquid passage. The spacer members divide the at leastone enclosed accommodation chamber into a heat-absorbing zone andcondensing zone. The heat-absorbing zone and the condensing zone aredisposed in communication with each other through the vapor passages andthe at least one liquid passage. The at least one piece of first wickmaterial has a part thereof disposed in the at least one liquid passage,and the other part thereof respectively disposed in the heat-absorbingzone and the condensing zone. The working fluid is filled in the atleast one enclosed accommodation chamber.

Thus, the arrangement of the multiple vapor passages and the at leastone liquid passage in the heat spreader effectively overcomes theproblem of low mass flux of working fluid in the prior art designs dueto vapor-liquid co-existence, achieving better working fluid cycleefficiency and enhancing heat dissipation performance.

Further, the spacer members are elongated members stopped between thefirst panel and the second panel. When compared to the support structureconsisting of two solid semi-spheres of unequal radius of the prior artdesign, the invention provides a better supporting effect.

Other advantages and features of the present invention will be fullyunderstood by reference to the following specification in conjunctionwith the accompanying drawings, in which like reference signs denotelike components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a heat spreader in accordance with a firstembodiment of the present invention.

FIG. 2 is a front view of the first embodiment of the present invention,illustrating the internal structure of the heat spreader.

FIG. 3 is a longitudinal sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a cross sectional view of the heat spreader in accordance withthe first embodiment of the present invention.

FIG. 5 is a front view illustrating the internal structure of a heatspreader in accordance with a second embodiment of the presentinvention.

FIG. 6 is a front view illustrating the internal structure of a heatspreader in accordance with a third embodiment of the present invention.

FIG. 7 is an exploded view of a part of the heat spreader in accordancewith the third embodiment of the present invention.

FIG. 8 is a schematic side view of the heat spreader in accordance withthe third embodiment of the present invention.

FIG. 9 is an exploded view of a heat spreader in accordance with afourth embodiment of the present invention.

FIG. 10 illustrates cylindrical support blocks arranged in theheat-absorbing zone and the condensing zone of heat spreader inaccordance with the fourth embodiment of the present invention.

FIG. 11 illustrates long columnar support blocks arranged in theheat-absorbing zone of heat spreader in accordance with the fourthembodiment of the present invention.

FIG. 12 illustrates long columnar support blocks arranged in theheat-absorbing zone and the condensing zone of heat spreader inaccordance with the fourth embodiment of the present invention.

FIG. 13 is an exploded view of a heat spreader in accordance with afifth embodiment of the present invention.

FIG. 14 is an exploded view of an alternate form of the heat spreader inaccordance with the fifth embodiment of the present invention,illustrating the second wick material disposed in the second panelwithin the heat-absorbing zone.

FIG. 15 is an exploded view of another alternate form of the heatspreader in accordance with the fifth embodiment of the presentinvention, illustrating the second wick material disposed in the secondpanel within the heat-absorbing zone and the condensing zone.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, a heat spreader with a liquid-vapor separationstructure in accordance with a first embodiment of the present inventionis shown. The heat spreader 10 comprises at least one first panel 11, asecond panel 12, a plurality of spacer members 13, at least one piece offirst wick material 14 and a working fluid (not shown).

The at least one first panel 11 is bonded to the second panel 12. Inthis first embodiment, the number of the at least one first panel 11is 1. Further, the first panel 11 and the second panel 12 definetherebetween at least one enclosed accommodation chamber 121. In thisfirst embodiment, the number of the at least one accommodation chamber121 is 1. Further, at least one vapor discharge tube 19 is disposed inthe connection area between the first panel 11 and the second panel 12.In this first embodiment, the number of the at least one vapor dischargetube 19 is 1. The vapor discharge tube 19 has one end thereof disposedin communication with the accommodation chamber 121, and an opposite endthereof extended out of the heat spreader 10 and blocked.

The multiple spacer members 13 are disposed inside the accommodationchamber 121 and abutted between the first panel 11 and the second panel12. Further, the spacer members 13 are arranged spaced apart from oneanother, thereby defining a plurality of vapor passages 141 and at leastone liquid passage 142. In this first embodiment, the number of the atleast one liquid passage 142 is 2. Further, the multiple spacer members13 device the accommodation chamber 121 into a heat-absorbing zone H anda condensing zone C. The heat-absorbing zone H and the condensing zone Care disposed in communication with each other by means of the multiplevapor passages 141 and the two liquid passages 142. Further, aheat-insulating zone A is defined in the accommodation chamber 121between the heat-absorbing zone H and the condensing zone C. Themultiple spacer members 13 are mounted in the heat-insulating zone A. Inthe present first embodiment of the present invention, the multiplespacer members 13 have an elongated shape; the multiple vapor passages141 and the two liquid passages 142 respectively exhibit an elongatedshape (see FIGS. 1, 2 and 4).

The at least one piece of first wick material 14 has a part thereofmounted in the two liquid passages 142. In this first embodiment of thepresent invention, the number of the at least one piece of first wickmaterial 14 is 2. The other part of these two pieces of first wickmaterial 14 is disposed in the heat-absorbing zone H and the condensingzone C. In this first embodiment of the present invention, these twopieces of first wick material 14 have an elongated shape. Further, thesetwo pieces of first wick material 14 fill up the liquid passages 142.These two pieces of first wick material 14 can be fiber tows, copperpowder or copper mesh (not shown). In this first embodiment of thepresent invention, these two pieces of first wick material 14 are fibertows (see FIGS. 1 and 2)

The working fluid is filled in the accommodation chamber 121. Sincetechnical filed of the working fluid is obvious to any person skilled inthe art and difficult to display in the figure, it is unnecessary torepeat them here.

After understanding the structural details of this first embodiment ofthe present invention, the application of this first embodiment isexplained hereinafter.

As illustrated in FIGS. 1-4, when the heat spreader 10 is at work, theheat-absorbing zone H transfers heat energy to the accommodation chamber121, causing the working fluid in the two pieces of first wick material14 to be vaporized into vapor phase. The working fluid will then gothrough the multiple vapor passages 141 in between the multiple spacermembers 13 in the form of vapor phase, and then diffuses into thecondensing zone C. When reached the condensing zone C, the working fluidcan be reduced to liquid phase and adhered to the condensing zone C, andthen guided by the two fiber tows of the first wick material 14 throughthe two liquid passages 142 between the condensing zone C and theheat-absorbing zone H to flow back to the heat-absorbing zone H. Themultiple vapor passages 141 and the two liquid passages 142 constrainthe vapor phase and liquid phase working fluid to flow in differentpassages, increasing the mass flux of the working fluid in thevapor-liquid circulation system. The multiple spacer members 13 areabutted between the first panel 11 and second panel 12 of the heatspreader 10 to form a sturdy support structure, achieving a bettersupporting effect. The use of the two elongated pieces of first wickmaterial 14 in the heat spreader 10 effectively accelerates thecirculation of the working fluid in the heat spreader 10. Physically,using fiber tows for the two pieces of first wick material 14 achievesmore mass flux of the working fluid than that using sintered copperpowder and copper mesh.

Accordingly, by the above-described first embodiment of the presentinvention, it is apparent that the arrangement of the multiple vaporpassages 141 and the two liquid passages 142 in the heat spreader 10effectively overcomes the problem of low mass flux of working fluid inthe prior art designs due to vapor-liquid co-existence, achieving betterworking fluid cycle efficiency and enhancing heat dissipationperformance.

As stated above, the multiple spacer members 13 are elongated membersabutted between the first panel 11 and second panel 12 of the heatspreader 10. When compared to the support structure consisting of twosolid semi-spheres of unequal radius of the prior art design, theinvention provides a better supporting effect.

Referring to FIG. 5, a heat spreader 20 in accordance with a secondembodiment of the present invention is shown. This second embodiment issubstantially similar to the aforesaid first embodiment with theexceptions as follows:

The second panel 22 has a second wick material 28 sintered thereto. Thissecond wick material 28 can be disposed in the second panel 22 withinthe heat-absorbing zone H2 and/or the condensing zone C2. In this secondembodiment, the two pieces of first wick material 24 are disposed incontact with the second wick material 28.

The second wick material 28 can be selected from copper powder or coppermesh. In this second embodiment, the second wick material 28 is a coppermesh.

In this second embodiment, a respective certain area of the second wickmaterial 28 is respectively sintered to the heat-absorbing zone H2 andthe condensing zone C2 in the second panel 22 of the heat spreader 20,enabling the heat-absorbing zone H2 to have a relatively higher workingfluid carrying capacity. Further, the second wick material 28effectively and evenly carries the working fluid, enhancing theevapotranspiration efficiency of the working fluid. Further, thearrangement of the second wick material 28 in the condensing zone C2inside the second panel 22 significantly increases the working fluidcarrying capacity of the condensing zone C2, improving the refluxefficiency of the working fluid during cycling. The other structuralfeatures of this second embodiment and the effect this second embodimentcan achieve are same as the aforesaid first embodiment, and thus, it isunnecessary to repeat them here.

Referring to FIGS. 6-8, a heat spreader 30 in accordance with a thirdembodiment of the present invention is shown. This third embodiment issubstantially similar to the aforesaid first embodiment with theexceptions as follows:

The second panel 32 further comprises at least one recessed portion 322located in the condensing zone C3. In this third embodiment, the numberof the at least one recessed portion 322 is 2; the second panel 32further has a third wick material 38 sintered thereto and located at abottom side of each of the two recessed portion 322. Further, the thirdwick material 38 is connected with the first wick material 34. Further,the height of the two recessed portions 322 is greater than the heightfrom the at least one first panel 31 to the second panel 32 (see FIG.8). In this third embodiment, the number of the at least one first panel31 is 2. These two first panels 31 are bonded to the second panel 32.Further, two enclosed accommodation chambers 321 are defined between thetwo first panels 31 and the second panel 32. Each accommodation chamber321 has arranged therein a plurality of spacer members 33, aheat-absorbing zone H3, a condensing zone C3, a plurality of vaporpassages 341, two liquid passages 342, two pieces of first wick material38 and a working fluid (not shown).

The third wick material 38 can be selected from copper powder or coppermesh. In this third embodiment, the third wick material 38 is made fromcopper mesh.

In this third embodiment, the added structure of the two recessedportions 322 of the heat spreader 30 increase the working fluid storagecapacity of the condensing zone C3; the two pieces of first wickmaterial 34 are used to guide the working fluid from the condensing zoneC3 back to the heat-absorbing zone H3. Further, changing the number ofthe component parts of the heat spreader 30 can relatively changing thecooling efficiency. The other structural features of this thirdembodiment and the effect this third embodiment can achieve are same asthe aforesaid first embodiment, and thus, it is unnecessary to repeatthem here.

Referring to FIG. 9, a heat spreader 40 in accordance with a fourthembodiment of the present invention is shown. This fourth embodiment issubstantially similar to the aforesaid first embodiment with theexceptions as follows:

The second panel 42 further comprises a plurality of support blocks 49corresponding to the heat-absorbing zone H4 and/or the condensing zoneC4. In this fourth embodiment, the support blocks 49 are mounted in thesecond panel 42 within the heat-absorbing zone H4. Further, thesesupport blocks 49 are cylindrical blocks. Further, the number of the atleast one piece of first wick material 44 in this fourth embodiment is4. These support blocks 49 are stopped against the first panel 41.Further, these support blocks 49 are respectively arranged at twoopposite lateral sides of the first wick material 44 within theheat-absorbing zone H4 to keep the first wick material 44 in position.Further; the support blocks 49 can aligned with one another, or arrangedin staggered rows. In this fourth embodiment, the support blocks 49 arealigned with one another. Further, the support blocks 49 arerespectively arranged in alignment with the spacer members 43, forming aplurality of equally spaced support member sets 45. Further, except theaforesaid configuration, the support blocks 49 can also be arranged inthe second panel 42 corresponding to the heat-absorbing zone H4 and thecondensing zone C4 (see FIG. 10) and, the support blocks 49 can beconfigured to have a long columnar shape (see FIGS. 11 and 12).

In this fourth embodiment, the support blocks 49 of the heat spreader 40can be arranged in the second panel 42 corresponding to theheat-absorbing zone H4 and/or the condensing zone C4 to effectivelyenhance the structural strength of heat spreader 40. The otherstructural features of this fourth embodiment and the effect this fourthembodiment can achieve are same as the aforesaid first embodiment, andthus, it is unnecessary to repeat them here.

Referring to FIG. 13, a heat spreader 50 in accordance with a fifthembodiment of the present invention is shown. This fifth embodiment issubstantially similar to the aforesaid first embodiment with theexceptions as follows:

The second panel 52 has multiple support blocks 59 arranged thereincorresponding to the heat-absorbing zone H5 and/or the condensing zoneC5. In this fifth embodiment, the support blocks 59 are cylindricalblocks arranged in the second panel 52 within the heat-absorbing zoneH5; the number of the at least one piece of first wick material 54 is 4.Further, the support blocks 59 are stopped against the first panel 51,and disposed at two opposite lateral sides of the multiple pieces offirst wick material 54 within the heat-absorbing zone H5 to hold themultiple pieces of first wick material 54 in position. These supportblocks 59 can aligned with one another, or arranged in staggered rows.In this fifth embodiment, the support blocks 59 are aligned with oneanother. Further, the support blocks 59 are respectively arranged inalignment with the spacer members 53, forming a plurality of equallyspaced support member set 55.

Further, except the aforesaid configuration, the support blocks 59 canalso be arranged in the second panel 52 corresponding to theheat-absorbing zone H5 and the condensing zone C5. Further, the supportblocks 59 can be configured to have a long columnar shape (not shown).

The heat spreader 50 in accordance with this fifth embodiment of thepresent invention further comprises a second wick material 58 located inthe second panel 52 corresponding to the heat-absorbing zone H5 and/orthe condensing zone C5, and disposed in contact with the at least onepiece of first wick material 54. In this fifth embodiment, the secondwick material 58 is disposed in the second panel 52 within thecondensing zone C5. Further, the number of the at least one piece offirst wick material 54 is 4. Except the configuration described above,the second wick material 58 can be simply disposed in the second panel52 within the condensing zone C5 (see FIG. 14). Alternatively, thesecond wick material 58 can be disposed in the second panel 52 withinthe heat-absorbing zone H5 and the condensing zone C5 (see FIG. 15).

The structural arrangement of this fifth embodiment significantlyincreases the working fluid carrying capacity of the heat-absorbing zoneH5 and the condensing zone C5 while maintaining the structural strengthof heat-absorbing zone H5 and condensing zone C5 of the heat spreader50. The other structural features of this fifth embodiment and theeffect this fifth embodiment can achieve are same as the aforesaid firstembodiment, and thus, it is unnecessary to repeat them here.

Although particular embodiments of the invention have been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention. Accordingly, the invention is not to be limited except asby the appended claims.

What is claimed is:
 1. A heat spreader, comprising: at least one firstpanel; a second panel bonded with said at least one first panel anddefining with said at least one first panel at least one enclosedaccommodation chamber therebetween; a plurality of spacer membersabutted between said at least one first panel and said second panel andarranged spaced apart from one another in said at least one enclosedaccommodation chamber and defining a plurality of vapor passages and atleast one liquid passage, said spacer members dividing said at least oneenclosed accommodation chamber into a heat-absorbing zone and condensingzone, said heat-absorbing zone and said condensing zone being disposedin communication with each other through said vapor passages and said atleast one liquid passage; at least one piece of first wick materialhaving a part thereof disposed in said at least one liquid passage andthe other part thereof respectively disposed in said heat-absorbing zoneand said condensing zone; and a working fluid filled in said at leastone enclosed accommodation chamber.
 2. The heat spreader as claimed inclaim 1, wherein said heat-absorbing zone and said condensing zonedefine a heat-insulating zone therebetween; said spacer members aredisposed in said heat-insulating zone.
 3. The heat spreader as claimedin claim 1, wherein said spacer members exhibit an elongated shape. 4.The heat spreader as claimed in claim 1, wherein said vapor passages andsaid at least one liquid passage respectively exhibit an elongatedshape.
 5. The heat spreader as claimed in claim 1, wherein said at leastone piece of first wick material exhibits an elongated shape and fillsup said at least one liquid passage.
 6. The heat spreader as claimed inclaim 1, further comprising at least one vapor discharge tube mounted inthe bonding area between said at least one first panel and said secondpanel, said at least one vapor discharge tube each having one endthereof disposed in communication with said at least one enclosedaccommodation chamber and an opposite end thereof extended out of thesaid heat spreader and blocked.
 7. The heat spreader as claimed in claim1, wherein said second panel has a plurality of support blocks mountedtherein corresponding to said heat-absorbing zone and/or said condensingzone and abutted against said at least one first panel and disposed attwo opposite lateral sides of said at least one first wick material tohold said at least one first wick material in position.
 8. The heatspreader as claimed in claim 7, wherein said support blocks areoptionally aligned with one another or arranged in staggered rows; saidsupport block are respectively disposed in alignment with said spacermembers, forming a plurality of support member sets.
 9. The heatspreader as claimed in claim 7, wherein said second panel furthercomprises a second wick material sintered thereto, said second wickmaterial being disposed in said heat-absorbing zone and/or saidcondensing zone and kept in contact with said at least one piece offirst wick material.
 10. The heat spreader as claimed in claim 1,wherein said second panel further comprises at least one recessedportion disposed within said condensing zone, and a third wick materialsintered to a bottom side of each said recessed portion and connectedwith said first wick material, the height of said at least one recessedportion being greater than the height from said at least one first panelto said second panel.
 11. The heat spreader as claimed in claim 1,wherein said at least one first wick material is selected from thematerial group of fiber tow, copper powder and mesh.